Dental flask



July 10, 1928.

M. L. AXELROD DENTAL FLASK Filed Jun'za, 192e Patented July l0, 1928.

Unirse srares l '1,676,677 ATEN'r OFI-fics. f

MEYER L. AXELROD, OF CILLEVJLAND,` OHIO, ASSGNOR TO OHO CHEMICAL & MANU-FACTURINGCOMPANY, OF CLEVELAND, OHIO, A CORPORATION OF OHIO.

DENTAL mask.

Application led June 28,

r This invent-ion relates to flasks for use by dentists and dentallaboratories for molding and vulcanizing rubber, molding and curingbakelite, and similar purposes. and its chief object is to provide aself-heating flask of simple and durable construction and reliableoperation which can be manufactured at reasonable cost. Another objectis to provide a self-heating flask in which the temperature is underthermostatic control so that a predetermined temperature can bemaintained without attention by the operator, thereby preventing injuryto the mold contents by overheating. To these and other ends theinvention comprises the novel features hereinafter described.

One forni ot my improved flask is illustrated in the accompanyingdrawings, in which Fig. l is a perspective view oit the complete lask. I

Fig. 2 is a plan view (on .line 2 2, Fig. 8) ot' the lower part of theiiask, with the electrical heating element or coil in dotted lines.

Fig. 3 is a central cross section on the plane indicated at 3--3, Fig.1.

F ig. 4 is a diagram showiiig the preferred method of connecting theheating elements with a source of current.

The flask shown comprises separable upper and lower body portions 10,1l. The upper portion 10 has a removable cover provided with ears 14 toreceive screws l5 eX- tending through aligned ears 16 into bosses 17 onthe lower part to hold the two parts together under pressure. The lowerbody portion -11 has a removable bottom 18 provided with ears 19 alignedwith the bosses 17 to receive the screws 21 by which the said bottom 18is held in place. To insure proper assembly ot the parts the lower isprovided with recesses 22 alongside of the bosses 17, Fig. 2, to receiveclosely tit-ting fingers 23 on the upper part, as will be readilyunderstood.

The heating elements 24, 25, are housed in the cover 12 and bottom 18.which are made hollow for the purpose and are closed by means of innerplates 26, 27., removably secured by screws 28. The terminals of `thelower heating element are brought out to contact pins 29 carried by butinsulated :trom a bracket 8() mounted on the bottom 18. The cover 1.2may have a central hol- 1926. Serial No. 118,941, 1

low rib 31 to house a removable thermostat 32 carried by but insulatedfrom said rib. One end ot the thermostat (which is 'shown as theconventional two-metal type) is connected to the contact-.pin 33 andtheother is adapted to engage a contact 34 connected with one terminalot the heating element 24. The other terminal oi the heating element isconnected to contact pin 35, as clearly indicated in Fig. 4. The pins33,' 35 are carried by but insulated from a bracket 36 mounted on thecover 12. The heating elements 24, 25 are embedded in refractoryinsulating bodies 37, which may adhere to or be otherwise secured to theplates 26, 27.

Fig. 4 illustrates diagrammatically a convenient way ot connecting theheating elements to the source of current, not shown. ln this ligure, 40represents a cord having two conductors 41, 42, connected to terminalpins 43, 44, carried by an insulating plug,7 not shown. Conductors 4land 42 are connected at their other ends to sockets 45, 46, carried byinsulating caps, not shown, which latter also carry sockets 47, 48connected together by an insulated flexible conductor 49. lt will beapparent that when the pins 43, 44 are connected with the terminals of asource of current and pins 29, 33, 85 are plugged into the caps carryingthe sockets 45, 46, 47, 48, current will flow through the thermostat andheating elements in series. It' the temperature to which the thermostatis subjected rises above a predetermined point the thermostat tleXes andopens the circuit, closing it again when the temperature Jr'alls. Inthis way a substantially constant temperature is maintained, as will bereadily understood. For simplicity a non-adjustable thermostat is shown,but it will be understood that the invention is not limited to thattype. In order to vary the temperature with the type shown it isnecessary to remove the cover plate 2ok by taking out the screws,whereupon the thermostat may be removed and another substituted, tomaintain a higher or lower temperaturgLas may be desired.

he pressure needed in vulcanizing or curing can be applied by setting upthe screws 15. Preferably, however, these screws are used merely to holdthe parts together, the necessary pressure being applied by means of anysuitable press, not shown. For this purpose the bottom of the flask ismade flat, as indicated, Eand the top may be provided with `.radial ribs38, lush with the thermostat housing 3l, to distribute the pressure andthere avoid breakage of the cover, as will be readily understood: Thescrews 15 can then be set up and the flask removed, or it can remain inthe press during part or all of the period of heating.

My improved flask is convenient by reason of the fact that not only canthe two halves be separated, as is customary, but also the bottom andtopcan be removed. Moremimportant, however, is itsself-heating feature,whichadapts vit to vulcanization by dry heat instead oi by,steam.l This'feature is especially important in making bakelite dentures, asdescribed. in my copending application Serial No. 73,60l, liled December7, 1925, which the `hakelite must be kept dry while being` curedf It isto be understood that the invention is not limited to the specificconstruction herein illustrated and described but can be embodied inother forms without departure from its spirit.

l claim- A self-heating dental iiask composed of separable upper andlower sections having hollow upper and lower walls, electrical heatingelements housed in the top of t-he upper section and the bottom of thelower section,

means for connecting the heating elements with Va source of current, anda thermostat` MEYER L. AXELROD.

